JP2016157356A - Wireless sensor terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless sensor terminal having a solar cell module as a self-supporting power supply and exposed to a harsh outside environment, which is capable of favorably wirelessly transmitting a detection output of a sensor.SOLUTION: The wireless sensor terminal comprises a power supply circuit connected to a solar cell module and generating power supply voltage, a sensor receiving the power source voltage from the power supply circuit to detect an attribute of a detection object, a wireless transmission signal generation circuit for converting a detection signal of the sensor into a wireless transmission signal, and an antenna for emitting the wireless transmission signal as an electric wave. A package has a recess surrounded with a wall part. The power supply circuit, the sensor, and the wireless transmission signal generation circuit are placed in the recess so as to be covered by the solar cell module, and the antenna is buried in the wall part. When seen from the side of external light that the solar cell module receives, a face on which the solar cell module receives the external light and the wall part do not overlap each other. A lid part is joined to cover the recess of the package to thereby make a highly airtight structure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless sensor terminal suitable for use in a case where it is attached to a place exposed to a harsh external environment such as high temperature, high humidity, salt damage such as a bridge for a long time.

  For example, in order to preserve road infrastructure such as bridges, tunnels, road accessories, and slopes, a sensor network system that installs wireless sensor terminals on these bridges and collects sensor outputs sent from the wireless sensor terminals Is considered.

  This type of wireless sensor terminal is attached to a place exposed to a harsh external environment such as high temperature, high humidity, and salt damage for a long period of time, so that it is required to have a highly durable package structure.

  As this type of wireless sensor terminal, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-122718) proposes a wireless sensor node having a sealed structure using a ceramic package. That is, in the wireless sensor node disclosed in Patent Document 1, as shown in FIG. 11, a power generation unit 30 including a power generation element is provided in a hollow portion of a package 20 configured by stacking a plurality of ceramic layers. , An acceleration sensor 34, circuit units 35 and 37 for converting a detection signal of the acceleration sensor 34 into a radio signal, and an antenna 38 that radiates the radio signal as a radio wave are housed. The lid member 21 is integrally joined to the package 20 so that the cavity is hermetically sealed. Patent Document 1 describes that the lid member 21 may be made of ceramic in addition to being made of metal.

  The wireless sensor node of Patent Document 1 has a feature that it has resistance to an external environment at an installation place and does not depend on an external power source by using a package having a hermetic structure made of ceramic.

JP2013-122718A

  In the wireless sensor node disclosed in Patent Document 1, a vibration power generation element is used as a self-supporting power source. However, the vibration power generation element cannot generate power in an installation place where vibration cannot be obtained. Therefore, in most of the assumed external environment, sunshine is often obtained, and therefore it is conceivable to use a solar cell module using solar cells as the power generation element. In that case, it is desirable for the solar cell module to have a light receiving surface as large as possible so that light can be received as efficiently as possible.

  For example, in the wireless sensor node described in Patent Document 1, when a solar cell module is provided as a power generating element, a plate surface portion covering the inside of the package is made of a light-transmitting material, and the plate surface portion is The solar cell module is preferably arranged so as to cover the inside of the package so as to receive the transmitted light as much as possible.

  However, in Patent Document 1, an antenna is provided in a cavity inside the package. Since the solar cell module serves as an obstructive element for transmission / reception radio waves with respect to the antenna, the solar cell module cannot be disposed in the region where the antenna is disposed. For this reason, there exists a problem that the light-receiving surface of a solar cell module will become small by that much.

  FIG. 5 of Patent Document 1 also shows an example in which an antenna is disposed on the back side of the lid of the package. However, in this case, since the antenna is provided on the light incident side with respect to the light receiving surface of the solar cell module, the antenna blocks off incident light on the light receiving surface of the solar cell module, and the solar cell module. There is a problem that the entire light receiving surface cannot be used effectively.

  An object of the present invention is to provide a wireless sensor terminal capable of solving the above problems.

In order to solve the above problems, the invention of claim 1
A solar cell module;
A power supply circuit connected to the solar cell module and generating a power supply voltage;
A sensor for detecting a detection target attribute in response to a power supply voltage from the power supply circuit;
A wireless transmission signal generation circuit that generates a wireless transmission signal from a detection signal including information on the detection target attribute detected by the sensor;
An antenna that radiates the radio transmission signal generated by the radio transmission signal generation circuit as a radio wave;
The power supply circuit, the sensor, and the wireless transmission signal generation circuit are arranged in the recess so as not to shield the surface on which the solar cell module receives external light. And a package in which the antenna is embedded in the wall,
With
When viewed from the external light side received by the solar cell module, the surface on which the solar cell module receives the external light and the wall portion are areas that do not overlap each other,
A wireless sensor terminal is provided, wherein a member that covers at least the recess of the package is joined to the package to form a sealed structure.

  According to the wireless sensor terminal of the first aspect of the invention having the above-described configuration, the power supply circuit is configured so that the surface of the solar cell module receiving external light is not shielded by the recess of the package including the recess surrounded by the wall. And a sensor and a wireless transmission signal generation circuit are disposed, and an antenna is embedded in the wall. And when it sees from the external light side which a solar cell module receives, let the surface which a solar cell module receives external light, and a wall part be an area | region which does not mutually overlap. Therefore, according to the invention of claim 1, since the light receiving surface of the solar cell module and the arrangement position of the antenna do not overlap, the light receiving surface of the solar cell module can be maximized.

  According to a second aspect of the present invention, in the first aspect of the invention, the solar cell module has a flat plate shape, and the power supply circuit, the sensor, and the wireless transmission signal generation circuit in the recess are provided. The member that covers the entire region to be disposed and that covers at least the concave portion is made of a translucent material and is provided to face a surface of the solar cell module that receives external light. It is characterized by that.

  According to the invention of claim 2, the solar cell module can also be accommodated in the recess of the package. For this reason, compared with the case where a solar cell module is exposed outside, the high durability as a wireless sensor terminal is realizable.

  The invention of claim 3 is the invention of claim 1, wherein the solar cell module has a configuration in which a plurality of spherical solar cells are embedded in a light-transmitting material, and the appearance has a dome shape. And the member covering at least the recess is shared by the solar cell module.

  According to the invention of claim 3, since the solar cell module has a configuration in which a plurality of spherical solar cells are embedded in the translucent material, the solar cell module itself is provided with the recess of the package. As a covering member, it can be joined to a package to form a sealed structure.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the recess includes a predetermined material, the power supply circuit, the sensor, and the wireless transmission signal generation circuit in an air layer. It is filled so that it may not touch.

  According to the fourth aspect of the present invention, the power supply circuit, the sensor, and the wireless transmission signal generation circuit disposed in the recess are covered with the filled predetermined material so as not to contact the air layer. Therefore, according to the invention of claim 4, since the air layer does not touch the power supply circuit, sensor, and wireless transmission signal generation circuit arranged in the recess, high durability against humidity and the like can be easily realized. it can.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the predetermined material is filled so as to eliminate the hollow portion of the recess, and has a thermal conductivity equal to or higher than the thermal conductivity of the package. It is a material.

  In the invention of claim 5, the predetermined material filled so as to eliminate the hollow portion of the recess is a material having a thermal conductivity equal to or higher than the thermal conductivity of the package and having a good heat radiation characteristic. Therefore, the temperature rise in the package due to sunlight can be suppressed. For this reason, it is possible to prevent the power supply circuit, the sensor, and the wireless transmission signal generation circuit disposed in the recess from being exposed to high temperatures, and to ensure stable operation.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the power supply circuit is provided with a power storage unit that stores power energy from the solar cell module. And

  According to the wireless sensor terminal of the invention of claim 6, since the power energy from the solar cell module is stored by the power storage unit, it is stored in the power storage unit even in a situation where light that can be generated by the solar cell module is not incident. The operation can be continued by the electric power energy.

  According to the wireless sensor terminal of the present invention, the antenna is embedded in the recess of the package including the recess surrounded by the wall, and the solar cell module is viewed from the outside light received by the solar cell module. Since the surface receiving the external light and the wall portion do not overlap each other, the light receiving surface of the solar cell module and the arrangement position of the antenna do not overlap, and the light receiving surface of the solar cell module is maximized. It can be a size.

It is a figure which shows the structural example of 1st Embodiment of the wireless sensor terminal by this invention. It is a block diagram which shows the example of an electronic circuit structure of 1st Embodiment of the wireless sensor terminal by this invention. It is a figure for demonstrating the example of a structure of 1st Embodiment of the wireless sensor terminal by this invention. It is a figure for demonstrating the structural example of the principal part of 1st Embodiment of the wireless sensor terminal by this invention. It is a figure for demonstrating the example of a structure of 1st Embodiment of the wireless sensor terminal by this invention. It is a figure for demonstrating the sealing coupling | bonding method in 1st Embodiment of the wireless sensor terminal by this invention. It is a figure which shows the structural example of 2nd Embodiment of the wireless sensor terminal by this invention. It is a figure which shows the structural example of other embodiment of the wireless sensor terminal by this invention. It is a figure which shows the structural example of other embodiment of the wireless sensor terminal by this invention. It is a figure which shows the structural example of other embodiment of the wireless sensor terminal by this invention. It is a figure for demonstrating the structural example of the conventional wireless sensor terminal.

  Several embodiments of a wireless sensor terminal according to the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram for explaining a configuration example of a wireless sensor terminal 100 according to the first embodiment of the present invention. The wireless sensor terminal 100 according to the first embodiment is configured by providing each electronic circuit component constituting the wireless sensor terminal 100 in a package 101 having a rectangular parallelepiped shape whose appearance is substantially flat. FIG. 1B is a diagram showing the wireless sensor terminal 100 when the package 101 is viewed from a direction orthogonal to the surface on the side of taking in external light, as will be described later. FIG. 1A is a cross-sectional view taken along line AA in FIG. 1B and is a diagram for describing a configuration example in the package 101.

  The package 101 is a highly durable material capable of maintaining the performance of the internal circuit even when exposed to a harsh external environment such as salt damage, high temperature and high humidity. In this embodiment, the package 101 is a non-metallic material, Compared to the above, it is made of a ceramic material that has toughness, is lightweight, and has electrical insulation. As shown in FIG. 1A, the package 101 includes a box-shaped package main body 102 having an opening at the top and a recess 104 surrounded by a wall 102W, and a lid 103.

  In this embodiment, the package main body 102 is configured by stacking LTCC (Low Temperature Co-fired Ceramics) substrates. The lid 103 is made of a translucent ceramic material. The lid 103 is bonded to the package main body 102 at the end surface of the wall 102W via a bonding member 105 by low melting glass melting described in detail later. The structure is hermetically sealed.

  In this embodiment, the package main body 102 includes a signal processing circuit for detecting external environmental factors using a power supply system including a self-supporting power source and a plurality of sensors such as a vibration sensor and a temperature sensor, and wirelessly transmitting the detection output. An electronic circuit comprising the system is accommodated. Main components of this electronic circuit are accommodated in the recess 104 of the package body 102. However, as will be described later, the antenna for wireless communication is provided embedded in the wall 102W of the package body 102. The antenna to be embedded is formed of a conductor filled in vias penetrating at least one layer of the ceramic layer, formed in a pattern shape between the ceramic layers, or formed by a combination of vias and patterns.

[Electronic circuit configuration example]
FIG. 2 is a block diagram showing a configuration example of an electronic circuit of the wireless sensor terminal 100 of this embodiment. As shown in FIG. 2, the power supply system 200 of the wireless sensor terminal 100 of this embodiment includes a solar cell module 202 as an example of a first self-sustained power supply with respect to the power supply control circuit 201 and a second self-supported power supply. A vibration power generation element 203 as an example and a storage capacitor 204 are connected to each other.

  In the signal processing circuit system 210, a plurality of sensors such as a vibration sensor 212, a trigger sensor 213, and a temperature sensor 214 are connected to a processing control circuit 211 for controlling the entire wireless sensor terminal 100. A communication control circuit 215 is connected. An antenna 216 is connected to the communication control circuit 215. A power supply control circuit 201 is also connected to the processing control circuit 211.

  In this embodiment, the solar cell module 202 has a rectangular shape in which one or a plurality of flat-plate solar cells are arranged in a planar shape. The vibration power generation element 203 is configured as, for example, a MEMS (Micro Electro Mechanical System) using a piezoelectric element. The vibration power generation element 203 can also be used as the vibration sensor 212.

  In this example, the storage capacitor 204 is composed of one capacitor (capacitor), but may be composed of a plurality of capacitors. Further, the power storage capacitor 204 may be formed of an electric double layer capacitor.

  In this example, the power supply control circuit 201 is configured as an energy management LSI (Large Scale Integration), receives the power generation voltage from the solar cell module 202 and the power generation voltage from the vibration power generation element 203, and While generating the power supply voltage, the power storage capacitor 204 is charged with surplus power. When the power supply voltage cannot be generated from the power generation voltage from the solar cell module 202 or the power generation voltage from the vibration power generation element 203, the power supply control circuit 201 uses the power storage voltage stored in the power storage capacitor 204 as the power supply voltage. To do. By performing such power control, power control is performed so that the wireless sensor terminal 100 can maintain operation with a long lifetime.

  The vibration sensor 212 is for detecting the vibration of the place where the wireless sensor terminal 100 is attached as a detection target attribute. In this example, the vibration sensor 212 is configured as a MEMS sensor. The trigger sensor 213 is for detecting a sudden event such as an impact applied to the wireless sensor terminal 100 as a detection target attribute, and is also configured as a MEMS sensor in this example. The temperature sensor 214 is for detecting the temperature in the recess 104 of the package body 102 of the wireless sensor terminal 100 as a detection target attribute, and this is also configured as a MEMS sensor in this example.

  In this example, the processing control circuit 211 is configured by, for example, an MPU (Micro Processor Unit). The processing control circuit 211 has a time management function, and takes in vibration information and temperature information detected by the vibration sensor 212 and the temperature sensor 214 at a predetermined timing. Then, the processing control circuit 211 generates transmission information from the captured vibration information and temperature information, and wirelessly transmits the transmission information to the outside through the communication control circuit 215. In this example, the wireless transmission signal generation circuit includes a processing control circuit 211 and a communication control circuit 215.

  In this embodiment, transmission information generation and wireless transmission based on the vibration sensor 212 and the temperature sensor 214 are intermittently executed based on time management in the processing control circuit 211. Further, the processing control circuit 211 monitors the detection output of the trigger sensor 213, and when a sudden event is detected, the processing control circuit 211 generates transmission information based on the detection output of the trigger sensor 213 at the time of detection, and performs communication control. Wireless transmission to the outside through the circuit 215.

  The processing control circuit 211 also cooperates with the power supply control circuit 201 to perform power supply control to the vibration sensor 212, the trigger sensor 213, the temperature sensor 214, and the communication control circuit 215, and to control the power supply voltage in the wireless sensor terminal 100. Execute energy-saving control.

  The communication control circuit 215 converts the transmission information from the processing control circuit 211 into a signal of a predetermined modulation method, and generates a wireless transmission signal that is wirelessly transmitted through the antenna 216. In this example, the radio transmission signal has a carrier frequency (carrier frequency) of 920 MHz. In this embodiment, the communication control circuit 215 has not only a transmission function but also a reception function, and the processing control circuit 211 processes a signal received from the outside through the communication control circuit 215. And a function of a control processing circuit for performing predetermined control based on a processing result in the wireless reception signal processing circuit.

[Example of arrangement of electronic circuit components in package 101]
In this example, as shown in FIG. 1A, the inner surface on the recess 104 side of the wall 102W of the package main body 102 is on the recess 104 side from the bottom surface of the recess 104 to a predetermined height h1. It is configured to overhang. The height h1 is lower than the height h0 corresponding to the depth of the recess 104, that is, the distance from the bottom surface of the recess 104 to the end surface of the wall 102W of the package body 102 (h1 <h0). .

  Thus, a stepped portion 106 having a step shape is provided in the recess 104 of the package body 102 as shown in FIG. As shown in FIG. 1B, the stepped portion 106 is formed over the entire inner side of the four side wall portions 102W of the package main body 102. Therefore, the concave portion 104 has a small concave portion 104a surrounded by the step portion 106 and having a small cross-sectional area, and a large concave portion 104b surrounded by the wall portion 102W other than the step portion 106.

  In this example, the power source control circuit 201, the vibration power generation element 203, the storage capacitor 204, the processing control circuit 211, the vibration sensor 212, other than the solar cell module 202 and the antenna 216, are formed on the bottom surface in the small recess 104 a. A trigger sensor 213, a temperature sensor 214, and a communication control circuit 215 are arranged. In FIG. 1A, only the process control circuit 211, the vibration sensor 212, and the temperature sensor 214 are shown for convenience.

  As described above, in this embodiment, the package body 102 is configured by stacking LTCC substrates. As shown in FIG. 3, conductor patterns 107a, 107b, 107c, 107d,... Are provided between the LTCC substrates 102a, 102b, 102c, 102d,. , 102c, 102d,... Are electrically connected between the electronic circuit components shown in FIG. 2 by providing vias 108a, 108b, 108c, 108d,. Like to do.

  The wall portion 102W made of the LTCC substrate is provided with a via filled with a conductor for electrical connection between the power supply control circuit 201 and the solar cell module 202 disposed in the small recess 104a. In addition, electrical connection with the terminals of the solar cell module 202 is made at the end face of the stepped portion 106.

  As shown in FIGS. 1 and 4, the antenna 216 is disposed in the package 101 so as to be embedded in the wall portion 102 </ b> W of the package body 102. In this embodiment, the antenna 216 is composed of two rod-shaped conductors 216a and 216b, and is configured to be omnidirectional. That is, in this example, the rod-shaped conductor 216a is arranged so that the axial direction thereof is a direction along the height direction of the wall portion 102W, and the rod-shaped conductor 216b is arranged such that its axial direction is the wall portion. It arrange | positions so that it may become a direction orthogonal to the height direction of 102W.

  By arranging the two rod-shaped conductors 216a and 216b as described above, the directivity characteristics of the antenna 216 are obtained by combining the directivity characteristics of the antenna constituted by the two rod-shaped conductors 216a and 216b, respectively. Therefore, it can be made almost non-directional.

  These rod-shaped conductors 216a and 216b are formed by filling conductors into vias penetrating at least one layer of the LTCC substrate when the wall portion 102W is formed by stacking the LTCC substrates. To be contained within. Then, the electrical connection between the rod-shaped conductors 216a and 216b and the communication control circuit 215 is also performed by a conductor pattern (shown as a conductor pattern 107i in FIG. 1) between the stacked LTCC substrates as shown in FIG. .

  The solar cell module 202 of this embodiment has a rectangular flat plate shape as described above, and the rectangular shape portion is similar to the recess 104. The size (area) of the solar cell module 202 is larger than the cross-sectional area of the small recess 104a of the recess 104 of the package body 102 and smaller than the cross-sectional area of the large recess 104b. And the solar cell module 202 is accommodated in the large recessed part 104b in the state which the peripheral part collided with the part of the end surface of the level | step-difference part 106. FIG. The difference between the height h0 and the height h1, that is, the depth of the large recess 104b (= h0−h1) is selected to be larger than the thickness of the solar cell module 202.

  Therefore, the solar cell module 202 fits in the large recess 104b of the package body 102. For this reason, when viewed from the direction orthogonal to the lid 103, the solar cell module 202 is disposed at the wall portion of the package body 102 in which the two rod-shaped conductors 216 a and 216 b constituting the antenna 216 are embedded. It will not overlap with 102W. In other words, the antenna 216 is in a state where it can transmit and receive radio waves without being disturbed by the solar cell module 202 at all.

  The solar cell module 202 is electrically connected to the power supply control circuit 201 disposed in the small recess 104a through a conductor formed of a via provided in the wall 102W, and at the end surface of the step 106. For example, the small concave portion 104a is sealed by bonding with an adhesive or the like.

  In this case, the small recess 104a is filled with a predetermined filler 109, for example, a resin so that at least the electronic circuit component does not touch the air layer. By filling the filling material 109, the electronic circuit components disposed in the small recess 104a do not touch the air layer, so that the electronic circuit components in the small recess 104a are not rusted or corroded by moisture or moisture. And can have long-term airtightness. In particular, the vibration sensor 212 and the vibration power generation element 203 are configured as MEMS elements, but coupled with the airtightness of the package 101 to be described later, it is possible to prevent deterioration of the characteristics and maintain performance.

  Further, in this embodiment, the filler 109 is made of a high heat dissipation material having a high thermal conductivity that is equal to or higher than the thermal conductivity of the ceramic material (LTCC substrate) constituting the package body 102. The package body 102 has a thermal conductivity of 2 W / mk. In this example, the filler 109 is made of a material having a thermal conductivity of 4 W / mk, which is twice that of the filler 109. As a result, the package 101 itself made of a ceramic material is coupled with the fact that it has a high thermal conductivity and is a high heat dissipation material, so that the temperature rise in the small recess 104a is suppressed and the electronic circuit components in the small recess 104a operate stably. Can be secured.

  In addition, as an example of the method of filling the small concave portion 104a covered with the solar cell module 202 with the filler 109, the small concave portion 104a is filled with the filler 109 made of, for example, a gel-like resin, and the solar cell is formed thereon. A method is used in which the module 202 is joined at the step 106 to seal the small recess 104a. In this case, it is only necessary to prevent the electronic circuit components in the small recess 104 a from touching the air layer by the filler 109, so that there may be a slight space gap between the solar cell module 202 and the solar cell module 202.

  In addition, as an example of a method of filling the small concave portion 104a covered with the solar cell module 202 with the filler 109, a part of the step portion 106 is provided between the end surface of the step portion 106 and the side wall surface facing the small concave portion 104a. After forming holes (injection holes and air vent holes) communicating with the solar cell module 202 and sealing the small recesses 104a, the liquid filler 109 is injected through the holes in the formed step portions 106. When the filling is finished, a method of closing the hole formed in the stepped portion 106 may be used.

  As described above, the electronic circuit component is arranged in the small recess 104a, the inside of the small recess 104a is filled with the filler 109, and the small recess 104a is sealed by the solar cell module 202. When the lid 103 is sealed and bonded to the main body 102, the recess 104 is sealed, and the package 101 has airtightness.

  In this case, as described above, the lid 103 needs to transmit the incident light to the solar cell module 202 in the recess 104, and therefore, in this embodiment, the lid 103 is made of a translucent ceramic (alumina). . This translucent ceramic material has toughness as compared with glass, is light in weight, has electrical insulation, and has optical transparency. FIG. 5 shows a comparison table of main characteristics between the translucent ceramic and glass constituting the lid portion 103.

  As is apparent from the table of FIG. 5, the lid 103 made of translucent ceramic has higher thermal conductivity than glass, and the thermal conductivity (4 W / of LTCC) which is a ceramic material constituting the package body 102. mk), even if the temperature of the space of the large concave portion 104b rises due to incident light, there is an effect that heat is efficiently radiated through the lid portion 103. Furthermore, since the translucent ceramic has a higher heat resistance than glass, in this embodiment, the lid 103 made of the translucent ceramic is attached to the wall portion of the package body 102 by utilizing this high heat resistance. For example, a low-temperature, high-airtight sealing connection is performed on the end face of 102 W by, for example, local heating using a laser.

  When the package body 102 and the lid portion 103 are joined using a joining member, conventionally, heat is applied to the entire package body 102 and the lid portion 103 so that the temperature is higher than the melting temperature of the joining member. Then, the joining member is melted and then cooled to solidify the joining member. However, with this method, the temperature of the entire package 101 becomes high, and solder cannot be used for mounting electronic circuit components mounted inside the small recess 104a, resulting in an increase in mounting cost.

  Therefore, in this embodiment, as shown in FIG. 6, only the joint of the peripheral edge of the lid 103 and the end surface of the wall 102 </ b> W of the package main body 102 is heated by the laser LZ, so that the package main body 102 is heated. Then, the lid 103 is sealed and joined. In this embodiment, a low melting point material, in this example, a low melting point glass is used as the bonding member 105 provided between the end surface of the wall 102W of the package body 102 and the lid 103.

  Furthermore, in this embodiment, the heat radiation via 110 for radiating the heat generated by the laser LZ fills the wall portion 102W of the package body 102 with a conductor in the via that penetrates at least one layer of the LTCC substrate. Embedded and provided. In this example, the heat radiating via 110 is provided so as to penetrate through all the layers of the LTCC constituting the wall portion 102W and to expose the end portion to the end surface of the wall portion 102W of the package main body 102 so as to facilitate heat dissipation. ing.

  The heat radiating via 110 is configured by charging a conductor having a high thermal conductivity higher than the thermal conductivity of the ceramic material (LTCC substrate) constituting the package body 102 and having a good heat radiating property in the via. In this example, the via is filled with a material having a thermal conductivity of 4 W / mk or more, for example, silver, which is twice the thermal conductivity of the LTCC substrate. As shown in FIG. 1B, a plurality of the heat radiating vias 110 are provided in a wall portion 102W of the package main body 102 at a predetermined interval.

  When sealing and bonding the lid 103 to the package body 102, in this example, as shown in FIG. 6, the laser LZ is directed along the periphery of the lid 103 from the direction orthogonal to the lid 103. Irradiate to scan. Then, the joining member 105 made of low-melting glass between the lid 103 and the end surface of the wall 102W of the package main body 102 is melted, and the lid 103 and the end surface of the wall 102W of the package main body 102 are joined. Become. Thereafter, the irradiation of the laser LZ is stopped to cool the bonded portion, the low melting point glass is solidified, the lid portion 103 and the package body 102 are bonded, and the package 101 having a sealed structure is obtained.

  In this case, the wall 102W of the package main body 102 is heated by the irradiation of the laser LZ. However, the heating is local, the bonding member 105 is low-melting glass, and the plurality of heat dissipation vias 110 are formed. Even if the solder is used for the electrical connection between the electronic circuit components housed in the small recesses 104a of the package body 102 by efficiently radiating the wall 102W of the package body 102 due to the presence, The temperature does not become so high that the solder melts, and there is no problem with the electrical connection between the components.

  As shown in FIG. 1B, in the wireless sensor terminal 100 of this embodiment, the bottom side of the package body 102 is closer to the wall portion 102W than the wall portion 102W of the package body 102. A flange 102F is formed so as to protrude. And the through-hole 102Fa, 102Fb, 102Fc, 102Fd for attachment is formed in this collar part 102F, Through this through-hole 102Fa, 102Fb, 102Fc, 102Fd and the through-hole pierced by the attachment object part, for example, A bolt made of ceramic is allowed to pass through and can be fixed with a nut made of ceramic.

  When the through hole cannot be drilled in the attachment target portion, the bottom surface side of the package 101 is bonded to an object to be detected by the vibration sensor 212, for example, a bridge, a tunnel accessory, or a road accessory with an adhesive. However, since the area of the bonding portion and the bonding portion with the object to which the wireless sensor terminal 100 is to be attached is increased by the amount of the flange portion 102F, it can be more firmly attached and fixed to the object. I have to.

[Effect of the first embodiment]
As described above, according to the wireless sensor terminal 100 of this embodiment, the lid 103 made of translucent ceramic is bonded to the package main body 102 in which the LTCC substrate is laminated, and the bonding member made of low-melting glass. By sealing and bonding with 105, the package 101 can be made highly airtight. In this case, in the wireless sensor terminal 100 of this embodiment, a sensor such as a vibration sensor 212 and an electronic component such as a communication control circuit 215 and a processing control circuit 211 are housed in the package 101. Since the antenna 216 is accommodated in the wall 102W, a so-called all-in-one package structure can be obtained. Therefore, it is possible to realize a wireless sensor terminal that is robust enough to withstand external shocks and is lightweight.

  And since the solar cell module 202 is accommodated in the recessed part 104 of the package main body 102, the end surface of the wall part 102W of the package main body 102 is not covered with the solar cell module 202. Therefore, the antenna 216 embedded in the wall 102 </ b> W of the package body 102 can transmit and receive radio waves without being disturbed by the solar cell module 202.

  Further, in the wireless sensor terminal 100 of this embodiment, the package 101 is made entirely of a ceramic material without using a metal part that inhibits transmission and reception of radio waves, and the wall 102W of the package body 102 in which the antenna 216 is embedded is Since the high-frequency characteristics of the low-resistance conductor can be used for the LTCC substrate, the entire wireless sensor terminal 100 can be configured to have reliability and sensitivity, and stable antenna propagation characteristics. .

  In addition, since the antenna 216 has a non-directional configuration in which radio waves are radiated uniformly in all directions, the installation of the wireless sensor terminal 100 can be easily performed regardless of the position or direction. There is an effect.

  In addition, since the wireless sensor terminal 100 according to this embodiment has a configuration in which the package 101 is entirely made of ceramic, other problems when the package is made of metal can be avoided. That is, problems such as deterioration of durability due to rust generation in metal casing, problems of shielding radio waves and light by metal casing, damage of electronic parts due to eddy current flowing into package due to lightning strike, etc. It does not occur in the wireless sensor terminal 100 having the all-in-package configuration made of ceramic according to the embodiment.

  Further, in the wireless sensor terminal 100 of this embodiment, since the electrical connection terminals and the like are not exposed to the outside from the package 101, the high airtightness of the package 101 can be easily maintained, and moisture penetration is also possible. There is also an effect that it can be prevented.

  In the above-described embodiment, the electronic component arranged in the small recess 104a of the package body 102 is covered with the filling material so that the air layer is not touched. Will not deteriorate. In addition, since the filling material is made of a material having good heat dissipation characteristics, heat generated from the electronic component is also well radiated, and the wireless sensor terminal 100 can achieve a long life and ensure stable operation. There is also an effect that can be done.

  Therefore, the wireless sensor terminal 100 of this embodiment can be installed due to its high airtightness even under high temperature, low temperature, high salinity environment and high concentration gas.

  In the wireless sensor terminal 100 of the above-described embodiment, not only the solar cell module 202 is used as a self-supporting power source, but also another self-supporting power source, in the above-described embodiment, the vibration power generation element 203 is also used. Therefore, it can be used in an installation place where the time for receiving light is small. In addition, since the wireless sensor terminal 100 according to the above-described embodiment includes the power storage unit including the power storage capacitor 204, the surplus power of the solar cell module 202 and the vibration power generation element 203 that are independent power sources is stored. Even when the power supply voltage cannot be obtained from these independent power sources, there is an effect that the power can be driven using the power stored in the power storage unit.

  In addition, the sealing and bonding of the lid 103 to the package body 102 of the package 101 of the wireless sensor terminal 100 of the above-described embodiment is performed by using a bonding member made of low-melting glass and by local heating with a laser. Thus, an increase in temperature inside the package main body 102 can be suppressed, and solder can be used for electrical connection of electronic components arranged inside the package main body 102. Furthermore, in this embodiment, since the heat radiating via 110 is provided in the wall portion 102W of the package main body 102, an increase in temperature inside the package main body 102 can be more reliably suppressed.

[Second Embodiment]
In the above-described first embodiment, the solar cell module 202 is configured by using flat-plate solar cells, and in order to protect the solar cell module 202, the solar cell module 202 is housed inside the package body 102, and the lid The portion 103 is hermetically bonded to the package main body 102, whereby the highly airtight package 101 is configured.

  On the other hand, in the second embodiment, by using a solar cell module using a solar cell having a special shape as described below, the lid 103 is also used as the solar cell module. It can be omitted by configuring.

  FIG. 7 shows a configuration example of the wireless sensor terminal 100A of the second embodiment. The same reference numerals are given to the same parts as those of the wireless sensor terminal 100 of the first embodiment, and the details thereof are shown. Description is omitted.

  In the wireless sensor terminal 100A of the second embodiment, the lid 103 in the wireless sensor terminal 100 of the first embodiment described above is not used, and instead of the flat plate solar cell module 202, FIG. The configuration other than using the solar cell module 300 having a hemispherical dome shape as shown, that is, the configuration on the package body 102 side is the same as that of the wireless sensor terminal 100 of the first embodiment.

  The solar cell module 300 used in the wireless sensor terminal 100A of the second embodiment has a configuration in which many known spherical solar cells 301 are housed in a dome-shaped translucent member 302 having a predetermined thickness. Prepare. The spherical solar battery cell 301 has a spherical shape with a diameter of, for example, about 1 to 2 mm. Since the light receiving surface is a spherical surface, the spherical solar battery cell 301 can receive light from all directions, compared to a flat plate solar battery cell. It is designed to capture about three times as much light.

  In this example, the translucent member 302 is made of, for example, translucent ceramic. In the translucent member 302, a large number of spherical solar cells 301 are connected in series, in parallel, or directly. Provided connected in parallel. The terminals of the solar cell module 300 are led out from the end face of the translucent member 302. In the package main body 102, a recess 104A having a circular cross section is formed in accordance with the shape of the end face of the solar cell module 300. The recess 104A of the package body 102 is provided with a stepped portion 106A as in the first embodiment, whereby the recess 104A is composed of a small recess 104aA and a large recess 104bA. Yes.

  And after the terminal derived | led-out from the end surface of the solar cell module 300 is connected with the conductor which consists of the via | veer formed in the level | step-difference part 106 of the package main body 102 comprised by laminating | stacking an LTCC board | substrate, Similarly to the first embodiment, the end surface of the solar cell module 300 is sealed and joined to the stepped portion 106 </ b> A of the package body 102 by the joining member 105 </ b> A made of low-melting glass. In this case, the laser LZ for local heating for sealing and bonding by the bonding member 105A is irradiated from a slightly oblique direction through the light transmitting member 302 of the solar cell module 300 made of light transmitting ceramic. In this case, not only the end surface of the solar cell module 300 and the end surface of the stepped portion 106A are sealed and joined, but also between the inner wall surface of the large recess 104b and the peripheral side surface in the vicinity of the end surface of the solar cell module 300. It is preferable to perform sealing and joining with a joining member made of low melting point glass.

  The wireless sensor terminal 100A according to the second embodiment configured as described above has the same operational effects as the wireless sensor terminal 100 according to the first embodiment described above, and is simple in that the lid 103 is unnecessary. The effect of having the configuration is obtained. Further, the configuration using the solar cell module 300 has an effect that the power generation amount (integrated power generation amount) throughout the day can be increased with higher efficiency than that of the flat plate solar cell module 202. In addition, there is an effect that high performance can be exhibited even on a cloudy day.

  In the example of FIG. 7, the stepped portion 106A is provided in the recess 104A of the package main body 102 as in the first embodiment. However, the solar cell module 300 can be sealed and bonded to the end face of the wall 102W of the package body 102 so as not to overlap the area of the antenna 216 embedded in the wall 102W. It is not necessary to provide the step portion 106A.

  Further, in the example of FIG. 7, the package body to which the solar cell module 300 is bonded is diverted from the package body 102 of the first embodiment as it is, but the package body is also formed in a cylindrical shape with a flat appearance. It may be.

[Other Embodiments or Modifications]
<About external terminals>
In the wireless sensor terminals 100 and 100A of the above-described embodiment, an external terminal for connecting to an external device or component is not provided. However, components such as sensors that are not provided inside the package main body 102 are arranged outside the wireless sensor terminals 100 and 100A, and components such as sensors arranged outside the package main body 102 and the inside of the package main body 102 are arranged. It would be convenient if it could be connected to the processing control circuit 211 or the like.

  8A and 8B show a configuration example of the wireless sensor terminal 100B in consideration of connection with a component such as a sensor arranged outside. The wireless sensor terminal 100B in the example of FIG. 8 is illustrated as applied to the wireless sensor terminal of the first embodiment, and the same parts as those of the wireless sensor terminal 100 illustrated in FIG. It is.

  The wireless sensor terminal 100B of this example includes an external terminal 111 exposed on the outer surface of the wall portion 102 of the package body 102 and the outer surface of the flange portion 102F. Other configurations are the same as those of the wireless sensor terminal 100 shown in FIGS. 1 (A) and 1 (B).

  In the wireless sensor terminal 100B of this example, the external terminal 111 is connected to the processing control circuit 211 inside the package main body 102 via the conductor pattern of the LTCC substrate. It goes without saying that which circuit inside the package body 102 is connected to the external terminal depends on the use of the external terminal and is not limited to being connected to the processing control circuit 211.

  Note that the external terminal 111 only needs to be used as necessary, and thus it is not always necessary to expose the external terminal 111, and a cover that covers the external terminal 111 so as to be openable and closable may be provided. It is further preferable that the cover is configured so that it can be opened when connecting to a component such as an external sensor and the connection part can be covered when the connection is completed.

<About antenna matching circuit>
In the description of the above embodiment, the arrangement of the antenna matching circuit provided between the antenna 216 and the communication control circuit 215 is omitted. However, the antenna matching circuit is provided in the small recess 104 a of the package body 102. Alternatively, it may be provided in the wall 102W of the package body 102. If necessary, the antenna matching circuit can be installed in the communication control circuit 215.

  FIG. 9 is a diagram illustrating an example of the wireless sensor terminal 100C in which the antenna matching circuit 217 is provided in the small recess 104a of the package main body 102. FIG. 10 illustrates the antenna matching circuit 218 in the wall of the package main body 102. It is a figure which shows the example of wireless sensor terminal 100D provided in the part 102W. 9 and 10 show the case of the wireless sensor terminal of the first embodiment, and the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

  The antenna matching circuits 217 and 218 are impedance adjustment circuits provided between the antenna 216 and the communication control circuit 215, and include a capacitive element and an inductance element. The antenna matching circuits 217 and 218 are not limited to a lumped constant circuit including a capacitive element and an inductance element, but may be a distributed constant circuit or a combination of a lumped constant and a distributed constant. In the example of FIG. 9, a conductive pattern 1070 is formed on the bottom surface of the small recess 104 a of the package body 102. An antenna matching circuit 217 is provided between the antenna 216 and the communication control circuit 215 on the bottom surface of the small recess 104 a of the package body 102.

  In the example of FIG. 10, an antenna matching circuit 218 composed of a capacitive element and an inductance element is embedded in a position between the antenna 216 and the communication control circuit 215 in the wall 102W of the package body 102. Provided.

<Others>
In the first embodiment described above, the solar cell module 202 is configured to cover the concave portion 104 of the package main body 102. However, the present invention is not limited to this configuration, and the solar cell module 202 transmits external light. It may be a part that can be received and disposed at a position that does not cover the recess 104. Also in this case, when viewed from the external light side received by the solar cell module, the surface where the solar cell module receives the external light and the wall portion are areas that do not overlap each other.

  Further, in the above-described embodiment, the antenna 216 is composed of two rod-shaped conductors in order to obtain characteristics close to omnidirectionality. However, the antenna 216 may be composed of one conductor, or a rod-shaped conductor. It is not limited to those made of conductors, and may be made of conductors of various shapes. Needless to say, the antenna 216 may be composed of three or more antenna conductors when the antenna 216 has characteristics closer to omnidirectionality.

  In the above-described embodiment, the vibration sensor, the trigger sensor, and the temperature sensor are used as the sensor. However, these are only examples, and are not limited to these sensors. The wireless sensor terminal of the present invention detects the sensor. Needless to say, a sensor corresponding to the attribute to be detected is provided in the package.

DESCRIPTION OF SYMBOLS 100 ... Wireless sensor terminal 101 ... Package, 102 ... Package main body, 102W ... Wall part of package main body, 103 ... Cover part, 104 ... Recessed part, 105 ... Joining member, 106 ... Step part, 107a, 107b, 107c, 107d ... Conductor pattern, 108a, 108b, 108c, 108d ... via, 202 ... solar cell module, 203 ... vibration power generation element, 204 ... storage capacitor, 211 ... processing control circuit, 212 ... vibration sensor, 215 ... communication control circuit, 216 ... Antenna 300 ... Solar cell module 301 ... Solar cell

Claims (12)

A solar cell module;
A power supply circuit connected to the solar cell module and generating a power supply voltage;
A sensor for detecting a detection target attribute in response to a power supply voltage from the power supply circuit;
A wireless transmission signal generation circuit that generates a wireless transmission signal from a detection signal including information on the detection target attribute detected by the sensor;
An antenna that radiates the radio transmission signal generated by the radio transmission signal generation circuit as a radio wave;
The power supply circuit, the sensor, and the wireless transmission signal generation circuit are arranged in the recess so as not to shield the surface on which the solar cell module receives external light. And a package in which the antenna is embedded in the wall,
With
When viewed from the external light side received by the solar cell module, the surface on which the solar cell module receives the external light and the wall portion are areas that do not overlap each other,
A member that covers at least the recess of the package is joined to the package to form a sealed structure. The solar cell module has a flat plate shape, and the power supply circuit, the sensor, and the wireless transmission signal generation circuit are provided in the recess so as not to shield a surface on which the solar cell module receives external light. Placed,
The wireless sensor terminal according to claim 1, wherein at least the member covering the recess is made of a light-transmitting material and is provided to face a surface of the solar cell module that receives external light. The solar cell module has a configuration in which a plurality of spherical solar cells are embedded in a translucent material, and has an external appearance having a dome shape, and the member covering at least the recess is the solar cell module The wireless sensor terminal according to claim 1, wherein the wireless sensor terminal is also used. The said recessed part is filled with the predetermined material so that the said power supply circuit, the said sensor, and the said radio | wireless transmission signal generation circuit may not touch an air layer. The wireless sensor terminal according to 1. 5. The wireless sensor according to claim 4, wherein the predetermined material is a material that is filled so as to eliminate the hollow portion of the recess and has a thermal conductivity equal to or higher than the thermal conductivity of the package. Terminal. The wireless sensor terminal according to claim 1, wherein the power supply circuit is provided with a power storage unit that stores power energy from the solar cell module. The package is configured as a laminate of a plurality of ceramic layers,
The antenna is composed of a conductor filled in a via penetrating at least one of the plurality of ceramic layers,
The solar cell module, the power supply circuit, the sensor, the wireless transmission signal generation circuit, and the antenna are electrically connected via a conductor provided between the stacked ceramic layers. The wireless sensor terminal according to claim 1, wherein the wireless sensor terminal is performed. The member that covers the at least the concave portion is made of translucent ceramic, and the sealing portion for forming the hermetic structure is a bonding portion by melting of low-melting glass. Wireless sensor terminal. The wireless sensor terminal according to claim 8, wherein a via filled with a material having a thermal conductivity equal to or higher than the thermal conductivity of the package is formed in the wall portion. The wireless sensor terminal according to any one of claims 1 to 9, wherein the antenna embedded in the wall portion includes two or more antennas having different directivity directions. The power generation element includes a vibration power generation element in addition to the solar cell module, and the power storage unit also stores power energy from the vibration power generation element. Wireless sensor terminal. The wireless sensor terminal according to any one of claims 1 to 11, wherein an antenna matching circuit is provided between the wireless transmission signal generation circuit and the antenna in the recess.

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